Hospital bed



Nov. 17, 1959 F. J. BURST HOSPITAL BED Filed Oct. 4, 1957 3 Sheets-Sheet 1 INVENTOR.

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F. J. BURST HOSPITAL BED Nov. 17, 1959 3 Sheets-Sheet 2 Filed Oct. 4, 1957 FT E1 INVENTOR fifm ifiwiw. ATTOENEYfi.

F. J. BURST HOSPITAL BED Nov. 17, 1959 3 Sheets-Sheet 5 Filed Oct. 4, 1957 HTTO/Ql/EY.

United States Patent i HOSPITAL BED Francis J. Burst, Batesville, Ind., assignor to Hill-Rom Company, Inc., Batesville, Ind., a corporation of lindiana Application October 4, 1957, Serial No. 688,164 9 Claims. (Cl. -60) This invention relates to hospital type bed wherein the height of the bed and the relative elevation of head and foot rest portions thereof are adjustable in motor powered operations carried out under remote control, as through readily manipulative control devices accessible to the hand of a person reclining upon the bed. More particularly, the invention is concerned with electrical operating and control means including an electric motor furnishing the power source and an electrical control circuit for selectively connecting movable parts of the bed in a driven relation to the motor in conjunction with an energizing of the motor for rotation in a selected direction.

An object of the invention is to provide a hospital type bed as described in which response to the manual operating controls is essentially electrical in nature, with a consequent increase in simplicity of structure and in the speed and certainty of response to operation of the controls. M

Another object of the invention is to enable some or all of the power operations of the bed to be temporarily disabled by means not readily accessible to the hand of a person reclining upon the bed.

A further object of the invention is to prevent misoperation as might result from the simultaneous actuation of more than one of the operating controls, it being an attendant object in this connection to accomplish this purpose electrically and Without the use of mechanical interlocks and the like.

A still further object of the invention is to make a power operated hospital type bed as described a substantially unitary structure in which the motor, the electrical control circuit and the means for activating the circuit are arranged in compact assemblies mounted upon and in effect becoming a part of the bed structure.

In the drawings:

Figure l is a top plan view, partly diagrammatic, of a hospital bed in accordance with the illustrated embodiment of the invention, upper parts of the bed being omitted in order that the construction and arrangement of operating units thereof may be more clearly seen;

Figure 2 is a fragmentary top plan view, enlarged with respect to Figure 1, showing the switch unit and the operating means therefor;

Figure 3 is a view in cross section through the power transmission or sprocket wheel box which connects the drive motor to the means for raising and lowering the movable parts of the bed; and

Figure 4 is a diagrammatic view of the electrical circuit and parts associated therewith provided for the energizing of the motor under remote control and for the selective connecting of the motorto the means for raising and lowering the bed parts.

Referring to Figure 1 of the drawings, a hospital type bed in accordance with the instant embodiment of the invention comprises a relatively stationary frame made up of side rails and 11, a transverse head rail 12, a

2,9123% Patented Nov. 17, ress "ice transverse foot rail 13, and a transverse seat section 14. The seat section 14 is elevated relatively to the balance of the described frame assembly and forms a part of the spring frame further including head rest and foot rest portions (not shown) pivotally connected to the seat section at their one ends and extending in opposite directions therefrom respectively toward the head end and the foot ends of the bed. I

The bed frame assembly comprising the parts described is mounted for vertical relative motion upon corner posts or feet 15 in a manner not here shown. To each of the four posts 15 extends a respective cable 1619 con nected from the frame to the foot in such manner that an axial pulling motion upon the several cables simultaneously serves to elevate the described frame assembly. The cables 16 and 17 are passed about superposed pulley wheels 21 (one shown) mounted on a bracket 22 in the seat section 14. Similarly, the cables 18 and 19 are passed about superposed pulleys 23 (one shown) on the bracket 22. Beyond the pulley wheels 21 and 23, the free ends of the cables 16-49 enter one end of a tube 24, the other end of which receives a screw shaft 25. The latter has a threaded connection with a nut 26 held against rotary motion in the tube 24 but permitted freedom of axial travel in response to rotation of the screw shaft. The cables 161-9 are connected, as indicated, to the nut 26. Accordingly, in response to one direction of rotation of the screw shaft 25, the nut 26 is drawn axially inward or to the right as viewed in Figure 1 within the tube 24 thereby to pull upon the several cables and elevate the bed frame assembly as described. An opposite direction of rotation of thescrew shaft results in a relative advance of the nut 26 within the tube 24, permitting the frame assembly to descend by gravity downward upon the feet 15.

Other tubes 27 and 28 parallel the tube 24 and are connected at their one ends respectively to the head rest portion, aforementioned, of the spring frame and to the foot rest 'portion thereof. The opposite ends of the tubes 27 and 28 receive respective screw shafts 29 and 31 which latter shafts have a threaded connection with nuts 32 and 33 within the respective tubes. The nuts 32 and 33 are pinnedor otherwise connected to the tubes in which they are received in a manner to prevent relative rotary motion thereof. Thus, rotation of the shafts 29 and 3 1 in one direction serves to extend the tubes relatively to the shafts and the result is to raise or to elevate the bed parts to which the tubes are connected. Similarly, rotation of the screw shafts in the opposite direction serves to retract the tubes 27 and 28 and thereby to lower the described bed parts. It will be understood that the shafts 29 and 31 are normally independently operated and that the respective bed parts are normally raised and lowered singly and independently of one another.

The power for rotation of the screw shafts 25, 29 and 31 is derived from a reversible electric motor 34 mounted on the bed frame assembly. By virtue of appropriate gearing, the motor 34 drives a shaft 35 in right angle relation thereto. The latter enters a sprocket or transmission case 36 mounted on the foot of the bed on the transverse rail 13. The shaft 35 is connected to and drives a sprocket wheel 37 in the case 36 which, through a sprocket chain 38 effects a unison rotary driving motion of other sprocket wheels 39, 41 and 42. Also, as shown in Figure 3, the chain 38 encompasses an idler sprocket wheel 43 suitably adjustable in the case 36 to tension the chain 38. Also as shown in Figure 3, the sprocket wheel 39 is rotatably mounted on a shaft 44 mounted in hearings in opposite side walls of the case 36. Further, the wheel 39 carries a friction disc 45 engageahle by a part 46 of an electric clutch 47 keyed or otherwise suitably secured to the shaft 44 for rotation therewith. The electric clutch 47, it will be understood, comprises electro magnetic means and an armature responsive to the energizing of such means to extend the part into frictional contact with the disc 45. In response thereto, the motion of the sprocket wheel 39 is transmitted to the electric clutch 47 which thus rotates with the wheel 39 and carries with it the shaft 44 which accordingly has rotation within its end bearings. The haft extends through and beyond the case 36, at one thereof, and continues beneath the transverse rail 3, where it is received in one end of a universal joint 6 by which the shaft 44 is connected to the previously mentioned screw shaft 25. Rotation of the shaft 44 thus is etfective to rotate the shaft 25 and so efiect either a raising or a lowering of the entire bed assembly depend ing upon the direction of rotation of the shaft 44. This is, of course, determined by the direction of rotation of the sprocket wheel 39 which is in turn a function of the direction of rotation of the motor 34.

in a manner like that above described, the sprocket wheel 42 is effective upon energizing of an electric clutch 49, to rotate a shaft 51 and thereby to rotate the screw shaft 29 by which adjustment of the head rest portion of the bed is achieved. Also, the rotary motion of the sprocket wheel 41 is utilized through an electric clutch 52 to turn a shaft 53 connected to the screw shaft 31. The several sprocket wheels 39, 41 and 42 rotate continuously with running of the motor 34 and in accordance with the instant inventive concept are selectively coupled to their respective shafts whereby independently to achieve any one of a raising and lowering of the bed proper, or a raising and lowering of either of the head rest or foot rest portions of the bed.

The selective clutching of the motor to difierent movable parts of the bed is accomplished by remote control from a panel 54 mounted on the seat section 14 for convenient access to the hand of a person reclining on the bed (Figure 1). On the panel 54 is a cam 55 operated by a finger piece 56 which serves to actuate a core wire 57a in one end of a Bowden cable 57 (Figure 2). Similarly, a cam 53 on the panel is operated by a finger piece 59 and actuates a wire 61a in a cable 61, while a cam 62 is operated by a finger piece 63 and operates a wire 64:: in a cable 64. The cables 57, 61 and 64 extend remotely from the panel 54 to the foot end of the bed where they enter a switch unit 65. Within the unit 65, the cable 61 is attached to one side of a U-shaped bracket 66. The core wire 61a of the cable 61 extends into the bracket 66 between the sides thereof and is attached to a cam 67 rotatably mounted on an upstanding post 68. The pivot post 68 is located between the point of attachment of the wire 61a to the cam and a head portion 69 thereon which is received between opposing plungers 7i and 72 of switches 73 and 74. Through manipulation of the cam 62, on the control panel 54, the core wire 61a may be either pushed or pulled within the cable 61 and so may effect a rocking motion of the cam 67 in either a clockwise or a counterclockwise direction as viewed in Figure 2. Normally, the head portion 69 of the cam occupies a neutral position between the plungers 71 and 72 with neither switch actuated. Rotary motion of the cam in a clockwise direction, however, depresses plunger 72 and actuates switch 74. Similarly, rotation of the cam 67 in a counterclockwise direction out of neutral position depresses plunger 71 and actuates switch 73.

In like manner, the manipulation of the cam 62 on the control panel 54 results in the imparting of a pushing or pulling motion upon the core wire 64a of cable 64 and consequent rotary adjustment of a cam 75 and consequent alternative depression of plungers 76 and 77 which are respectively parts of switches '73 and 79. Also, the core wire 57a in the cable 57 is connected to a cam 81 operating upon plungers 82 and 83 forming parts of respective switches 84 and 85.

The several pairs of switches 7374, 78-79 and 84- 85 are used to transform or to achieve from a single manipulative movement of a control cam on the panel 4 the energizing of the motor 34 for rotation in a selected direction and also the selection of a particular electric clutch 47, 49 or 52 for energizing. Thus, referring to the circuit diagram of Figure 4, as shown therein, each of the described switches is a two-position, multiple blade assembly, in which provision is made not only for energizing the motor 34 and for energizing the respective clutches 47, 49 and 52 but also to preclude misoperation as might result from a depression of a switch from two different pairs of switches simultaneously. The switches are substantially identical so that a description of one will suffice for all. Thus, switch 73 is made up of six pairs of contacts 8691 and three jointly movable contact blades 929='i. The blade 92 makes alternate engagement with sets of contacts 86 and 87. The blade 94 makes alternate engagement with the sets of contacts and 39 and the blade 94 makes alternate engagement with the sets of contacts 91 and 2. The blade assembly tends to assume a position, as under the influence of a spring 95, wherein the blades bridge respective contacts 87, 89 and 92. Depression of the plunger '71 is effective, as for example through a lever 96 pivoted on a stud 97 to raise the switch blade assembly against the urging of spring 95 to engage the individual blades with their alternate sets of contacts.

- Upon release of the plunger '71 the switch blade assembly reassumes its normal position as urged by spring 95. The spring may thus further be utilized as a force tending to center the cam 67 in a neutral position and to restore the cam 58 to a neutral position when released from the hand of the operator.

The several switches are variably connected in the electrical circuit but, in each instance, the contacts 92 which are normally bridged by the switch blade 94, are in a conductor 98 which is common to all of the cir cuits and which forms one side of the incoming power supply line, the other side of which is represented by a conductor )97 The latter is connected directly to the motor 34. Other principal parts of the circuit include a motor relay conductor 101 extending from the motor to junction points or terminals 102 and 103 whence branch lines thereof extend to one of the contacts 88 in each of the several switches. The connection of the power supply line 98 to the motor is completed by way of alternate circuits adapted respectively to provide diiferent directions of rotation of the motor. Conductor 104 extending from the motor is a part of the up travel circuit since the energizing of the motor through this circuit results in a direction of rotation being imparted to the selected screw shaft which will raise that part of the bed affected thereby. Similarly, a conductor 105 leads from the motor and is part of the down travel circuit, so called because when the motor is energized through this circuit a direction of rotation of the selected screw shaft results which lowers the affected part of the bed. The conductor 104 extends to junction points 106 and 107. From the junction point or terminal 106 branches of the conductor 104 extend to the other one of the contacts 88 in the case of switches 79 and 85 and to contacts 87, 89 and 91 in the case of switch 84, there being an extension thereof from the other contact 89 of switch 84 to contact 91 of switch 78. Similarly, the contacts 87 of switch 84 are connected by a further extension of the up travel circuit through the contact 87 of the switch 78 to the contact 91 of switch 74. The terminal W7 is connected to one of the contacts 03 of switch 73 and is still further connected by a conductor 108 to a rectifier 109 supplying an electric clutch circuit 111.

The down travel circuit represented by conductor 105 extends from the motor to a terminal 112 whence extend leads to the other contacts 88 of switches 74, 78

and 84. Also from the terminal 112.extends a lead to contacts 87, 89 and 91 of switch 85. An extension thereof is directed from contacts 89 of switch 85 to contact 91 of switch 79. A similar .extension from the contact 87 of switch 85 passes through the contacts 87 of switch 79 and proceeds to contact 91 of switch 73. The contacts 91 of the several switches accordingly are supplied on one side thereof from the up travel circuit 104 in some instances and from the down travel circuit 105 in other instances. In the case of each switch, the other contact 81 is connected by a lead 113 to power supply line 98. Accordingly, dependent upon which of the several switches is operated, the power supplied the motor 34 will be such as to energize the motor for rotation in a selected direction. Actuation of switch 73, for example, closes a circuit through the down travel conductors while actuation of switch 74 closes a circuit through the up travel side of .the system.

The electric clutch operating circuit includes the conductor 111 as a power supply line and the contacts 86 of each of the several switches which are both connected in the circuit in a parallel manner. Thus, by way of example, from the rectifier 109, the conductor 111 extends directly to a terminal 114 from which extensions of the conductor lead to corresponding contacts in the pairs of contacts 86 in the respective switches 84 and 85. The other contact of each pair is connected to a terminal 115 from which extends a conductor 116 to one side of the electro magnetic part of the electric clutch 47, the other side of such part being connected to a return conductor 120 tied into a terminal 120a in the circuit 105. According to the construction and arrangement of parts, therefore, actuation of either switch 84 or 85 serves to bridge the contacts 86 therein with the result that power is supplied to the electric clutch 47 for energizing thereof. The pair of switches 73 and 74 in similar manner control the supply of power to electric clutch 49 while the pair of clutches 78 and 79 control the supply of power to the electric clutch 52. The return conductor 120 is common to the clutches 49 and 52.

In these latter instances, however, there further is interposed in the circuits other remote control or safety switches 117 and 118. In the aforementioned supply line 111 is a terminal 119 from which extends an extension 121 of the power supply line to the switch element 117. From the later extends conductor 122 to a terminal 123 which is connected to corresponding contacts 86 in the switches 73 and 74. The other contacts 86 are connected to a terminal 124 from which extends a lead 125 to the electric clutch 49. The switch 117 is normally closed and hence imposes no control over the normal operation of the system. Movement of the switch out of its normal position, however, will interrupt the supply of power to the contacts 86 of the switches 73 and 74. These switches, controlling the adjustment of the head rest portion of the bed accordingly are rendered disabled or made ineffective to initiate a lowering or raising of the head rest portion of the bed as long as the switch 117 remains actuated. This switch accordingly presents a safety device by which a bed patient may be prevented from making adjustments in the position of his head rest in the event that his condition or course of treatment requires that there be no elevation or change of elevation in the position of the head. The switch 118 operates with like effect with respect to the switches 78 and 79 controlling the adjustment of the foot rest portion of the bed. These switches are supplied, in a manner which may be seen, by an extension 121a of the conductor 121. Switch 118 is located in such extension and when actuated prevents a supply of current to the contacts 86 of either switch 78 or 79, consequently preventing the energizing of the electro magnet of electric clutch 52.

In the operation of the system, a control cam on the '6 panel 54 is adjusted to exert either a pulling or a pushing motion upon the core wire .of its associated Bowden cable. The respective cam, 67, 75 or 81 accordingly is rotated in the indicated direction with the result that one switch of the several pairs of switches is actuated. Considering by way of example, that switch 73 has been actuated, the switch assembly therein is shifted from the position shown to an alternate position wherein the contacts 86 are bridged by blade 93, contacts 88 are bridged.

by blade 94 and contacts 91 are bridged by blade 94. As a result thereof the power supply conductor 98 is connected to the motor by way of down travel circuit 105, the up travel circuit 104 being used in connection with the motor relay circuit 101 to close a circuit through the motor relay. This last-circuit is closed by the blade 94 bridging the contacts 88. As the switch 73 assumes its alternate position of adjustment, therefore, the motor 34 begins operation and transmits its movement through the sprocket wheels in case 36 which thus begin to turn in unison with running of the motor. At about the same time, the electric clutch 49 is energized with the result that the rotary motion of sprocket wheel 42 is transmitted through the clutch 49 to the shaft 51 and then through the universal joint to the screw shaft 29, turning the shaft in a direction to eifect a lowering of the head rest portion of the bed. This motion continues for as long as the operator holds the control cam 58 depressed or actuated. Upon release of the cam, the switch 73 is restored to control of the spring 95 which returns the spring blade assembly to the normal position illustrated, discontinuing the supply of power to the electric clutch and interrupting the circuit through motor 34.

The present invention contemplates, and the described circuit provides, a form of electrical interlock whereby the operation of a second switch, while a first actuated switch continues to be held operated, will stop the running of motor 34 thereby avoiding misoperation resulting from a conflict in supplied signals, as well as avoiding simultaneous operation of two or more parts of the bed. The arrangement by which power line 98 passes through each of the several switches is utilized to this end, as is the further circuitry by which the down travel conductor extends from the switch 73 to the motor 34 by way of intermediate switches 79 and 85, and by which the up travel conductor 104 reaches the motor 34 from switch 74 by way of intermediate switches 78 and 84. Thus, as may be seen, the actuation of switch 85, for example, results in power being supplied to the down travel circuit 105 through the switch bar 94 which moves from a position bridging contacts 92 to a position bridging contacts 91. The flow of current in supply line 98 is at this time down to the switch 84 and then through each of the switches 78, 74, 73 and 79 in series until the switch 85 is reached where the current is fed or supplied to the left handcontact 91 by the branch conductor 113. All of the other switches thus intervene in series relationship between the power source and the selected switch 85. Accordingly, an actuation of any one of the intervening switches to its alternate position will interrupt the supply of current to switch 85 and so stop the motor 34. The second operated switch will be unable to close a circuit through the motor, as long as the first actuated switch remains operated, since the supply line 98 will be open also with respect to this second operated switch. in the cases of switches 73 and 74 the operation of a second switch while one of these is held operated also will result in an opening .of the motor circuit either directly within the power supply line 98 in the manner above described or by virtue of the opening of one or the other of the down travel circuits or the up travel circuit 104. For example, if switch 73 is held aperated and the switch 79 moved to its alternate position the movement of the bar 94 from the contacts 92 in switch 79 will have no effect since the current supply through this switch already has been cutoff by earlier operation .of the switch '7 73. However, the current supply from switch 73 to the motor is at this time achieved through the switch 79 by way of the down travel circuit 105 by way of the pair of contacts 87 in switch 79 and the normally closed bar 93. The movement of this bar out of engagement with the contacts 87 will thus interrupt the current supply to the motor. While operation of a second switch will tend to close the electric clutch circuit the discontinuing of power supply to the motor will make the closing of the clutch circuit ineffective.

The invention also provides for an automatic, m a ical resetting of the switch operating cams 67, 75 and 31 to neutral position in the event of overtravel of a moving part of the bed. In the case of the foot rest elevating and lowering mechanism (Figure 2), the edge of cam 75 opposite the head portion 69 is formed with a cutout portion 127 defining spaced apart opposed shoulders engageable by a circular boss 128 on a rod 129 which has a sliding mounting in the sides of the U-shaped bracket 66. Relatively opposed compression springs I31 and 132 tend to hold the rod I29 in a normal position in which the collar or boss 128 is centered between the shoulders of the cut-out 127. When the core wire 62:: of cable 62 is pulled or pushed to rock the cam 75 and thereby to operate one or another of the switches '78 or 79 the came assumes a position in which one of the opposing shoulders of cut-out 127 lies adjacent to the collar 128. Now, an axial motion of the rod 129 in one direction will engage the collar 1'28 thereof with the adjacent shoulder on cam 75 and continued motion of the rod in the same direction will return the cam to neutral position, thereby permitting the affected switch to return to neutral position. At one end, the rod 129 extends through and beyond the bracket do and has an up turned end or finger portion 133 extending between tabs 1% and 135 secured to the tube 28. The tabs 134 and 135 are in such predetermined spaced apart relation as to define opposite maximum limits of travel for the tube. Thus, in a relative extending motion of the tube the tab 135 is engageable with the bent over finger 133 to move the rod I29 and thereby define a limit of extending motion for the tube. Similarly, in the retracting of the tube the the tab 134 engages the finger 133 and defines a limit of retracting movement.

The switches 73 and 74 are shown in Figure 2 in a position physically reversed from that indicated in the wiring diagram of Figure 4. In the illustrated embodiment of the invention, the construction and arrangement of parts is such that a relative extending motion of the tube 27 accomplishes the reverse of a relative extending motion of the tube 28. In order to obtain uniformity of control at the panel 54, however, the switches 73 and 74 are reversed so that an upward movement of a control cam 55, 58 or 62 will in all instances produce an elevating motion of the affected part of the bed and a downward motion of any control cam will effect a downward motion of the bed part controlled.

The switch assembly comprising switches 84 and 85, which controls the high-low positions of the bed, is the same as the assemblies described and illustrated for controlling the head and foot rest elevations, but it is for convenience of installation turned to a position 90 distant from the other assemblies.

Having thus described my invention, I claim:

1. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, rotatable screw shafts for shifting said sections, and a reversible motor mounted beneath the frame for rotating said screw shafts, the improvement which comprises, respective normally disengaged electrical clutches interconnecting said power motor individually with said rotatable screw shafts, respective pairs of control switches mounted beneath the frame, the switches of each pair being normally open and being in electrical connection with a respective electrical clutch for energizing the same,

thereby to establish a driving connection between said motor and a selected shaft, the switches of each pair being in electrical connection with said motor for energizing the motor in a forward or reverse direction concurrently with the energization of the selected clutch, and respective manually shiftable remote control means connected to each pair of switches, said remote control means shiftable in opposite directions for closing one switch of a selected pair upon movement in either direction, thereby to energize said motor in a forward or reverse direction and to energize a selected electrical clutch, said remote control means extending to a point above said frame for operation by a person reclining on the bed.

2. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, rotatable screw shafts for shifting said sections, and a reversible motor mounted beneath the frame for rotating said screw shafts, the improvement which comprises respective normally disengaged electrical clutches interconnecting said power motor individually with said rotatable screw shafts, respective pairs of control switches mounted beneath the frame, the switches of each pair being normally open and being in electrical connection with a respective electrical clutch for energizing the same, thereby to establish a driving connection between said motor and a selected shaft, the switches of each pair being in electrical connection with said motor for energizing the motor in a forward or reverse direction concurrently with the energization of a selected clutch, manually shiftable remote control means connected to each pair of switches, said remote control means shiftable in opposite directions for closing one switch of a selected pair upon movement in either direction, thereby to energize said motor in a forward or reverse direction and to energize a selected electrical clutch, said remote control means extending to a point above said frame for operation by a person reclining on the bed, and a decommissioning switch interconnected with said clutches and mounted at a point remote from a person reclining on the bed for deenergizing said motor.

3. In a hospital bed of the type having a frame, sections pivotally mounted above said frame, respective rotatable screw shafts for shifting said sections, and a reversible motor mounted beneath said frame for driving said screw shafts, the improvement which comprises, respective normally disengaged electrical clutches interconnecting said motor individually to said screw shafts, respective pairs of switches mounted beneath the frame, the switches of each pair being normally open and being in electrical connection with a respective electrical clutch for energizing the clutch when either switch of the pair is closed, thereby to establish a driving connection from said motor through said energized clutch to a selected screw shaft, the switches of each pair being in electrical connection with said reversible motor for energizing the same in a forward or reverse direction concurrently with the energization of the selected clutch, a control panel mounted at a point above said frame in a position for operation by a person reclining on the bed, respective flexible control cables extending from said panel to said pairs of switches, and manually actuated control devices mounted on said control panel and connected respectively to said cables, said cables being respectively connected to said pairs of switches for selectively closing a switch of each pair in response to actuation of said manually operated devices in either direction.

4. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, respective rotatable screw shafts for shifting said sections, and a reversible motor mounted beneath said frame for driving said screw shafts, the improvement which comprises, respective normally disengaged electrical clutches interconnecting said motor individually to said screw shafts,

respective pairs of switches mounted adjacentsaidscrew shafts beneath the frame, the switches of each pair being normally open and being in electrical connection with a respective electrical clutch for energizing the clutch when either switch of the pair is closed, thereby to establish a driving connection from said motor through said energized clutch to a selected screw shaft, the switches of eachpair being in electrical connection with said reversible motor for energizing the same in a forward or reverse direction concurrently with the energization of the selected clutch, a control panel mounted at a point above said frame in a position for operation by a person re- ,clining on the bed, respective flexible cables extending from said panel to said pairs of switches, a core wire extending through each of said cables for longitudinal motion in either direction relative to the cable, and manually actuated control devices mounted on said control panel and in driving connection with said core wires, said wires being respectively connected to said pairs of switches for selectively closing a switch of each pair in response to actuation of said manually operated devices in either direction.

5. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, respective rotatable screw shafts for shifting said sections, and a reversible motor mounted beneath said frame for driving said screw shafts, the improvement which comprises, respective normally disengaged electrical clutches interconnecting said motor individually to said screw shafts, respective pairs of switches, the switches of each pair being normally open and being in electrical connection with a respective electrical clutch for energizing the clutch when either switch of the pair is closed, thereby to establish a driving connection from said motor through said energized clutch to a selected screw shaft, the switches of each pair being in electrical connection with said re versible motor for energizing the same in a forward or reverse direction concurrently with the energization of the selected clutch, respective switch mounting brackets mounted beneath the frame, said brackets providing a pair of spaced limbs, the switches of each pair being mounted upon said limbs and having plungers projecting inwardly toward one another, a cam element pivotally mounted for rocking motion between said limbs, said cam having a portion disposed between the ends of the said plungers and normally residing in an intermediate position with said switches open, said cam arranged to close the switches of each pair individually upon rocking motion of the cam in opposite directions, respective remote control cables connected to said cams for rocking the same, and a respective switch actuating device on the opposite end of each cable for shifting said cam and thereby selectively closing one of the switches of each pair.

6. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, rotatable screw shafts including axially movable elements for shifting said sections, and a reversible motor mounted beneath the frame for rotating said screw shafts and shifting said axially movable elements, the improvement which comprises respective normally disengaged electrical clutches interconnecting said power motor individually with said rotatable screw shafts, a respective pair of control switches in electrical connection with each electrical Y clutch for energizing the same, thereby to establish a driving connection between said motor and a selected shaft, the switches of each pair being in electrical connection with said motor for energizing the motor in a forward or reverse direction concurrently with the energization of the selected clutch, respective switch brackets each having a pair of opposed limbs, said brackets respectively mounted adjacent said axially movable elements of the bed, said pair of switches mounted on the limbs of said brackets and having opposed plungers projecting inwardly toward one aonther, a cam element movably mounted between said limbs and having a portion engaging said plungers for closing said switches individually, a remote control cable connected to each cam element for shifting the same in either direction, thereby to close a selected switch of the pair, each of said axially movable elements including means engageable with the adjacent cam element for shifting the same in a direction to open said switch at a limit of motion of the axially movable element, thereby deenergizing said motor and clutch at the respective limits of motion of said axially movable element. 1-

7. In a hospital bed of the type having a frame, shiftable sections pivotally mounted above said frame, rotatable screw shafts including axially movable elements .for shifting said sections, and a reversible motor mounted beneath the frame for rotating said screw shafts and shifting said axially movable elements, the improvement which comprises respective normally disengaged electrical clutches interconnecting said power motor individually with said rotatable screw shafts, a respective pair of control switches in electrical connection with each electrical clutch for energizing the same, thereby to establish a driving connection between said motor and a selected shaft, the switches of each pair being in electrical connection with said motor for energizing the motor in a forward or reverse direction concurrently with the energization of the selected clutch, respective switch brackets each having a pair of opposed limbs, said brackets respectively mounted adjacent the axially movable elements of the bed, said pair of switches mounted on said limbs and having opposed plungers projecting inwardly toward one another, a cam element pivotally mounted between said limbs for rocking motion and having a portion engaging said plungers for closing said switches individually, a remote control control cable connected to each cam element for rocking the same in either direction, thereby to close a selected switch of the pair, said cable extending to a point above said frame and including manual control means for actuating the same, a control rod slidably mounted in each switch bracket and extending parallel to the adjacent movable element, means on said nod engageable with said cam for rocking the same, and abutment means on said axially movable element, said rod having a portion engageable with said abutment means for shifting said rod axially at the limits of travel of said axially movable element and thereby shifting said control rod axially relative to the bracket, said control rod rocking said cam in a direction to open a closed switch to deenergize said motor and clutch at the respective limits of motion of said axially movable element.

8. In a hospital bed of the type having a frame, and an elevating mechanism for raising and lowering the frame, shiftable head and foot sections pivotally mounted above said frame, mechanical means including rotatable first and second screw shafts for respectively shifting said foot and head sections, and a reversible motor mounted beneath the frame for rotating said screw shafts and driving said elevating mechanism for raising and lowering the frame, the improvement which comprises first, second and third normally disengaged electrically responsive coupling members respectively interconnecting said reversible motor individually with said first and second rotatable screw shafts and with said elevating mechanism, first, second and third pairs of electrical control switches, the switches of each pair having first normally opened contacts in respective electrical circuit controlling connection with the first, second and third electrically responsive coupling members, whereby when one of the switches of said first pair is closed a driving connection is established between said motor and the frame elevating mechanism, when one of the switches of said second pair is closed a driving connection is established between the motor and said first shaft, and when one of said third pair of switches is closed a driving connection is established between the motor and the secand shaft, the switches in each pair also being in electrillll cal circuit controlling connection with said motor for energizing the motor in a forward or reverse direction concurrently with the energization of the selected electrically responsive coupling member, and electrical interlocking means effective to function so that only one of said electrically responsive coupling members can be energized at one time and the motor can be energized for rotation only in a single direction at one time, said electrical interlock means comprising a normally closed contact associated with each of said switches, each of said normally closed contacts being in series electrical connection and in circuit controlling relationship with said electrically responsive coupling members and said motor, whereby when more than one of said switches is operated its normally closed contacts are opened and the motor and electrically responsive coupling members are deenergized.

9. In a hospital bed of the type having a frame, and an elevating mechanism for raising and lowering the frame, shiftable head and foot sections pivotally mounted above said frame, mechanical means including rotatable first and second screw shafts for respectively shifting said foot and head sections, and a reversible motor mounted beneath the frame for rotating said screw shafts and driving said elevating mechanism for raising and lowering the frame, the improvement which comprises first, second and third normally disengaged electrically responsive coupling members respectively interconnecting said reversible motor individually with said first and second rotatable screw shafts and with said elevating mechanism, first, second and third pairs of electrical circuit completion devices mounted beneath said frame, said first,

second and third circuit completion devices being in respective electrical circuit controlling connection with one of said electrically responsive coupling members, Whereby when said first circuit completion device is actuated a driving connection is established between said motor and the frame elevating mechanism, when said second circuit completion device is actuated a driving connection is established between the motor and said first shaft, and when said third circuit completion device is energized a driving connection is established to the second shaft, power leads for energizing the motor in a forward or reverse direction concurrently with the energization of the selected electrically responsive coupling member, and a remote control unit disposable at a point above said frame for operation by a person reclining on the bed, said remote control unit including separate actuating elements for actuating said first, second and third circuit completion devices, the construction of said remote control unit being such that the area immediately adjacent to the patient is not exposed to electrical arcing.

References Cited in the file of this patent UNITED STATES PATENTS 2,344,397 Drexler et al Mar. 14, 1944 2,349,701 Buttikofer May 23, 1944 2,540,133 Miller Feb. 6, 1951 2,590,337 McNabb et al Mar. 25, 1952 2,630,720 Gambrill Mar. 10, 1953 2,802,219 Travis Aug. 13, 2,807,808 Wetzler Oct. 1, 1957 

